ROCKFORD — Just weeks after promoting a public safety campaign encouraging youths to understand their rights in dealing with police, NAACP Rockford Branch President Lloyd Johnston experienced his own contentious exchange with Rockford Police Department officers at his home.

Part of a national program primarily directed at minority youths called the "411 on the Five-0," Johnston taught children to protect themselves by knowing what to expect from police and how to assert their rights respectfully.

NAACP "Know Your Rights" cards remind youths never to run from police, to stay calm and to say the phrase "I do not consent to searches."

The phrase stems from the Fourth Amendment, which was designed to protect U.S. citizens from unreasonable searches and seizures by government agents, and especially against government intrusion into a home.

When officers D'Evyron Boone, Mark Castronovo and Adam Dreger knocked on Johnston's door late at night on Oct. 30 and asked to come inside to explain why they were there, Johnston asserted his right to decline.

But the officers were there to check on the welfare of Johnston's 24-year-old son, Lloyd Quincy Johnston III, creating a conflict between the officers' obligations and Johnston's rights.

Would the police have been within their rights to enter Johnston's home without a warrant?

"The official rule is that all searches conducted without a warrant are per se unreasonable and would violate the Fourth Amendment," said Marc Falkoff, associate professor of law at Northern Illinois University. "But that is subject to well-defined exceptions. And that's where all the action is because there aren't just a few exceptions. There are so many exceptions that they swallow the rule."

As NAACP president, Johnston has in the past challenged the justification of officer-involved shootings, and his efforts to teach young people about how to deal with police represent one attempt to prevent such shootings.

Johnston also is asked to observe the transfer of investigative authority from Rockford police to the Winnebago County Integrity Taskforce in cases in which an officer shoots someone — a measure instituted to reassure the community after the 2009 officer-involved shooting death of Mark Anthony Barmore. Johnston also serves on a police advisory board.

As a result, he has gotten to know Police Chief Chet Epperson and Terry Peterson, the police union president, Johnston said.

Johnston said the police on Oct. 30 responded aggressively to his refusal to allow them into his house. He asked the officers whether Peterson was on duty, wanting to request his presence. When Johnston couldn't find Peterson's number in his cell phone contacts, he called Epperson and conducted a conversation on speaker phone.

Johnston said Epperson had told him he was sending a supervisor, but that a claim in the official police report that Epperson had said to tell the officers "to leave" was false.

A copy of Boone's police report detailing the matter was obtained and aired by veteran WNTA radio host Ken DeCoster, who agreed to share it with the Rockford Register Star.

Johnston's ex-wife had reported to police that she heard a struggle over the phone while she had been talking with her son earlier that evening. She reported that the line then went dead. She also told police — falsely, Johnston said — that there was a history of physical altercations between the men.

Boone wrote in his report: "I explained to Lloyd, 'We (the police) were here in the capacity as community caretakers. We could not leave until we check the welfare of his son Quincy, even if we had to kick the door in.' Lloyd advised he knew the law and we (the police) could not enter his house unless we had a warrant."

A welfare check, however, is exempt from Fourth Amendment protection. Courts allow the police to enter a home in their role as community caretaker, Falkoff said.

Johnston said his negative response was partly a reaction to Boone's aggressive approach and threat to kick in the door.

"My ex-wife has done this before, and when officers have showed up before, I did not even have a problem with letting them in," Johnston said. "It was Officer Boone's immediate adversarial demeanor I picked up on when I said I am not going to let you in right now. He didn't appreciate that but ... he should have responded in a more diplomatic way."

Johnston's son, Lloyd Quincy Johnston III, said that there was no struggle for the phone while he was speaking to his mother.

He said that he has a good relationship with his father. The son said he had argued with his mother, who lives in New York, earlier in the night during a phone conversation.

"My dad said instead of arguing back and forth, just hang up, don't argue with her," he said.

He said he didn't know the police were there until his father already had declined to let them inside. When he heard the voices of police, he at first thought he was hearing a television show. When he realized the police were actually there, he worried police would falsely accuse him of something.

But when Sgt. Eddie Torrance arrived and explained the police could not leave until they had confirmed his well-being, Johnston III went outside to the porch to show he was not in harm's way.

The incident is under investigation, as is the identity of the person who leaked the police report. Meanwhile, the police union is raising questions about Epperson's phone conversation with Johnston and whether it obstructed their welfare check.

Union representatives also have raised concerns about officers being questioned by police commanders about the incident.

Falkoff, the NIU law professor, drew one lesson from the incident: Know your rights, but be judicious about when to attempt to assert them.

"You have to recognize the police may be authorized to do things you would rather they don't do," Falkoff said. "You need humility and a dose of common sense when interacting with police."